As is well known, an automotive lamp typically comprises a housing provided with a light-emitting opening in a front area, a plate-shaped or lens-shaped lamp cover which covers the light-emitting opening, and a light source disposed in a lamp chamber defined by the housing and the lamp cover. An inner wall of the housing is provided with an integral reflective layer or an independent reflector. In such an automotive lamp, when the light source is lighted, direct light generated from the light source and reflected light from the inner wall of the housing are together emitted through the lamp cover to accomplish the intended lighting function.
In recent years, however, not only the proper lighting function during lit conditions (i.e., when the lamp is on), but also improved outer appearance in the daylight is increasingly required of such an automotive lamp. In particular, in order to achieve glistening effect and deep clear view into the interior, it is a general practice, especially with a head lamp, to form a reflective layer on the inner wall of the housing in metallic tone by vapor deposition of aluminum, to design the surface so as to control the light path, and to form the lamp cover with a resin cover which is flat and smooth both on front and back surfaces and which has no lens function.
In above-mentioned lamp, however, improvement of the outer appearance relies solely on the combination of a deposited reflective film and a resin cover, and as a result, obtained appearance is unavoidably limited to a metallic tone (or, a silver color). In order to obtain colored outer appearance, coloring of the inner wall, the reflector or the lamp cover itself, is proposed. However, as a result of coloring, violation of the regulation governing color of vehicle lamp, for example, violation of the Safety Regulation for Road Vehicles, may happen.
Coating the portion of the reflector which does not contribute to reflection of irradiated light with coloring paint, a method adopted in some automotive lamp, has a drawback that it requires complicated process of coating or painting, and it is difficult to perform uniform coating on the reflector which has often a complicated three-dimensional shape. Actually, it is possible to obtain only very faint color in such coating.
Japanese Unexamined Patent Publication (Kokai) No. 10-241415, as shown in FIG. 1, discloses an automotive signal lamp comprising a reflector 32 and an outer cover 38, wherein optical distribution of light emitted from a signal lamp 30 is controlled by the reflector 32. In this automotive signal lamp, a non-transparent mask 34 is disposed between the reflector 32 and the outer cover 38, and the mask 34 is provided with a central opening 36 such that light from the reflector 32 passes through the central opening 36 and reaches the outer cover 38, and a concave reflective surface 40 that is covered with a clear colored layer 42 and is disposed so that it reflects light L incident from outside. Colored appearance can be obtained using this automotive signal lamp. However, since two reflectors have to be actually arranged, the structure is unavoidably complex and manufacturing process is also complicated accordingly, leading to increase of cost and overall size.